Pins with multiple alt-funcs for the same peripheral (eg USART_CTS_NSS)
need to be split into individual alt-funcs for make-pins.py to work
correctly.
This patch changes the following:
- Split `..._CTS_NSS` into `..._CTS/..._NSS`
- Split `..._RTS_DE` into `..._RTS/..._DE`
- Split `JTDO_SWO` into `JTDO/TRACESWO` for consistency
- Fixed `TRACECK` to `TRACECLK` for consistency
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.